The connecting word **because** connects the reason (there was no harvest), with the result (they had almost run out of food). (See: [[rc://en/ta/man/translate/grammar-connect-logic-result]])
The connecting words **But still** introduce a contrast relationship. You would expect the widow to refuse to help Elijah because she was almost out of food, but she did the unexpected and took care of him. (See: [[rc://en/ta/man/translate/grammar-connect-logic-contrast]])
This could be translated as: “God prevented their flour jar and their bottle of oil from becoming empty” or “God caused their flour jar and their bottle of oil to never become empty.”